For turbomachines such as gas turbines or aircraft engines, blade rings may be used in which a plurality of blade ring segments is assembled, each having at least one blade and an inner shroud and/or an outer shroud to form a blade ring. The blade profiles of the individual blade ring segments define an annular space between them through which the working gas flows, the annular space being delimited by the shrouds, and the shrouds have corresponding annular space delimiting surfaces.
Such blade ring segments are manufactured by casting or forging according to the prior art, forging being necessary to increase the strength when using newer and lighter materials in particular, e.g., TiAl materials. Blade ring segments manufactured accordingly must be remachined mechanically to achieve the desired surface shape by using electrochemical machining methods, for example, in which electrochemical material removal from the workpiece surface to be machined is achieved with the aid of working electrodes and suitable electrolytes. During electrochemical machining, the working electrode is brought in a linear movement close to the surface of the workpiece to be machined, so that a corresponding material removal takes place due to the potential set between the working electrode and the workpiece surface to be machined. Due to the linear movement of the electrode in the direction of the workpiece surface to be machined during the machining, the material removal varies, depending on the distance from the surface to be machined and the duration of the machining. Accordingly, due to a predefined path of movement of the electrode and the geometry of the blade ring segment, a height profile may develop along the end edge of shrouds of the blade ring segment, in particular in the case of end areas of outer shrouds, which are designed in a Z shape and are used for a form-locking connection of adjacent blade ring segments when the end edge of the shroud is situated at various distances from the electrode for different lengths of time. Due to the electrochemical machining of the shroud while the electrode is being moved over the Z-shaped end of the shroud, there is thus removal of different amounts of material along the Z-shaped edge, so that in the case of adjacent blade ring segments, steps appear between the annular space delimiting surface, which results in a negative influence on the flow conditions in the annular space.